Written as Langemarck on French, British and German maps, the village is known in military history as the scene (see trench map) of the first gas attacks by the German army in the western front, which marked the beginning of the Second Battle of Ypres in April 1915.

Before and during the First Battle of Ypres, the German reserve corps suffered enormous losses: over 10,000 young soldiers (some only 15 years old), led by young officers without practical experience, died without achieving any objective. On 10 November 1914, about 2,000 soldiers died during an attempted breakthrough. One day later, the German Command (Oberste Heeresleitung) published the following communiqué:

In west Langemarck, youth regiments singing Germany, Germany Above All advanced on front line enemy positions, broke and took them. Approximately 2,000 French line infantry and six machine guns were captured.

A popular and enduring myth of heroic self-sacrifice for the nation known as the "Mythos von Langemarck" arose from the propagandistic story.

The village was completely destroyed during World War I. There is now a major German war cemetery, the Langemark German war cemetery, (Soldatenfriedhof) in this location, which has about 40,000 burials.